Hi folks !
With CONFIG_POWER_SUPPLY=m & nouveau built-in we get a build failure:
drivers/built-in.o: In function `.nouveau_pm_trigger': (.text+0xa56e8): undefined reference to `.power_supply_is_system_supplied'
nouveau probably needs to depends on CONFIG_POWER_SUPPLY to force a module build with the latter is =m
Cheers, Ben.
On Mon, 2012-04-02 at 11:06 +1000, Benjamin Herrenschmidt wrote:
Hi folks !
With CONFIG_POWER_SUPPLY=m & nouveau built-in we get a build failure:
drivers/built-in.o: In function `.nouveau_pm_trigger': (.text+0xa56e8): undefined reference to `.power_supply_is_system_supplied'
nouveau probably needs to depends on CONFIG_POWER_SUPPLY to force a module build with the latter is =m
Ok, not that trivial...
The problem is more like POWER_SUPPLY should be a bool, not a tristate.
If you think about it: you don't want things like nouveau to depend on a random subsystem like that, people will never get it. In fact, POWER_SUPPLY provides empty inline stubs when not enabled, so that's really designed to not have depends...
However that -cannot- work if POWER_SUPPLY is modular and the drivers who use it are not. The only fixes here that make sense I can think of that don't also involve Kconfig horrors are:
- Ugly: in power_supply.h, use the extern variant if
defined(CONFIG_POWER_SUPPLY) || (defined(CONFIG_POWER_SUPPLY_MODULE) && defined(MODULE))
IE. use the stub if power supply is a module and what is being built is built-in. Of course that's not only ugly, it somewhat sucks from a user perspective as the subsystem now exists but can't be used by some drivers...
- Better: Just make the bloody thing a bool :-) The power supply framework itself is small enough, just make it a boolean option and avoid the problem entirely. The actual power supply sub drivers can remain modular of course.
Cheers, Ben.
Ok, not that trivial...
The problem is more like POWER_SUPPLY should be a bool, not a tristate.
If you think about it: you don't want things like nouveau to depend on a random subsystem like that, people will never get it. In fact, POWER_SUPPLY provides empty inline stubs when not enabled, so that's really designed to not have depends...
However that -cannot- work if POWER_SUPPLY is modular and the drivers who use it are not. The only fixes here that make sense I can think of that don't also involve Kconfig horrors are:
Ugly: in power_supply.h, use the extern variant if
defined(CONFIG_POWER_SUPPLY) || (defined(CONFIG_POWER_SUPPLY_MODULE) && defined(MODULE))
IE. use the stub if power supply is a module and what is being built is built-in. Of course that's not only ugly, it somewhat sucks from a user perspective as the subsystem now exists but can't be used by some drivers...
- Better: Just make the bloody thing a bool :-) The power supply
framework itself is small enough, just make it a boolean option and avoid the problem entirely. The actual power supply sub drivers can remain modular of course.
We can just do select POWER_SUPPLY.
Yes it reduces the option range for some stupid corner case but really I don't care, removing features from the kernel that a driver depends on is just leading to insane state combination and QA problems.
Dave.
On Mon, 2012-04-02 at 05:00 -0400, David Airlie wrote:
- Better: Just make the bloody thing a bool :-) The power supply
framework itself is small enough, just make it a boolean option and avoid the problem entirely. The actual power supply sub drivers can remain modular of course.
We can just do select POWER_SUPPLY.
Well, select'ing otherwise user configurable options was still frowned on last we discussed that... and it makes the whole inline stubs in power_supply.h totally pointless :-)
Yes it reduces the option range for some stupid corner case but really I don't care, removing features from the kernel that a driver depends on is just leading to insane state combination and QA problems.
Well, the power supply stuff only works if you have a backend for it, which not all platforms are, and it's fairly safe to assume AC whenever it's not actually supported.
(Talking of which, we should be able to do a PowerBook backend reasonably easily).
I don't care which solution you guys end up choosing though, just fix it :-)
Cheers, Ben.
Hello Benjamin,
Sorry, it took me some time to get to it.
On Mon, Apr 02, 2012 at 01:53:23PM +1000, Benjamin Herrenschmidt wrote: [...]
With CONFIG_POWER_SUPPLY=m & nouveau built-in we get a build failure:
drivers/built-in.o: In function `.nouveau_pm_trigger': (.text+0xa56e8): undefined reference to `.power_supply_is_system_supplied'
nouveau probably needs to depends on CONFIG_POWER_SUPPLY to force a module build with the latter is =m
Ok, not that trivial...
The problem is more like POWER_SUPPLY should be a bool, not a tristate.
I see that nouveau already selects POWER_SUPPLY, but your points are still valid. Let's make the power supply thing simple. I've applied the following patch:
- - - - [PATCH] power_supply: Make the core a boolean instead of a tristate
On Mon, Apr 02, 2012 at 01:53:23PM +1000, Benjamin Herrenschmidt wrote:
drivers/built-in.o: In function `.nouveau_pm_trigger': (.text+0xa56e8): undefined reference to `.power_supply_is_system_supplied'
nouveau probably needs to depends on CONFIG_POWER_SUPPLY to force a module build with the latter is =m
Ok, not that trivial...
The problem is more like POWER_SUPPLY should be a bool, not a tristate.
If you think about it: you don't want things like nouveau to depend on a random subsystem like that, people will never get it. In fact, POWER_SUPPLY provides empty inline stubs when not enabled, so that's really designed to not have depends...
However that -cannot- work if POWER_SUPPLY is modular and the drivers who use it are not.
The only fixes here that make sense I can think of that don't also involve Kconfig horrors are:
Ugly: in power_supply.h, use the extern variant if
defined(CONFIG_POWER_SUPPLY) || (defined(CONFIG_POWER_SUPPLY_MODULE) && defined(MODULE))
IE. use the stub if power supply is a module and what is being built is built-in. Of course that's not only ugly, it somewhat sucks from a user perspective as the subsystem now exists but can't be used by some drivers...
- Better: Just make the bloody thing a bool :-) The power supply
framework itself is small enough, just make it a boolean option and avoid the problem entirely. The actual power supply sub drivers can remain modular of course.
Suggested-by: Benjamin Herrenschmidt benh@kernel.crashing.org Signed-off-by: Anton Vorontsov cbouatmailru@gmail.com --- drivers/power/Kconfig | 2 +- include/linux/power_supply.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig index 99dc29f..0c52a40 100644 --- a/drivers/power/Kconfig +++ b/drivers/power/Kconfig @@ -1,5 +1,5 @@ menuconfig POWER_SUPPLY - tristate "Power supply class support" + bool "Power supply class support" help Say Y here to enable power supply class support. This allows power supply (batteries, AC, USB) monitoring by userspace diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index fd17ae0..3b912be 100644 --- a/include/linux/power_supply.h +++ b/include/linux/power_supply.h @@ -212,7 +212,7 @@ extern void power_supply_changed(struct power_supply *psy); extern int power_supply_am_i_supplied(struct power_supply *psy); extern int power_supply_set_battery_charged(struct power_supply *psy);
-#if defined(CONFIG_POWER_SUPPLY) || defined(CONFIG_POWER_SUPPLY_MODULE) +#ifdef CONFIG_POWER_SUPPLY extern int power_supply_is_system_supplied(void); #else static inline int power_supply_is_system_supplied(void) { return -ENOSYS; }
dri-devel@lists.freedesktop.org
-
Anton Vorontsov -
Benjamin Herrenschmidt -
David Airlie